so sánh 2020.2021-1/2020.2021 và 2021.2022-1/2021.2022

2 câu trả lời

`(2020 . 2021 - 1)/(2020 . 2021) = (2020.2021)/(2020 . 2021) - 1/(2020 . 2021) = 1 - 1/(2020 . 2021)`

`(2021.2022 - 1)/(2021.2022) = (2021.2022)/(2021.2022) - 1/(2021.2022) = 1 - 1/(2021.2022)`

Có:

`1/(2020 . 2021) > 1/(2021.2022)`

`=> 1 - 1/(2020 . 2021) < 1 - 1/(2021.2022)`

`=> (2020 . 2021 - 1)/(2020 . 2021) < (2021.2022 - 1)/(2021.2022)`

Vậy `(2020 . 2021 - 1)/(2020 . 2021) < (2021.2022 - 1)/(2021.2022)`

Đáp án

2020.2021-1/2020.2021= 2021-1/2020=2020.999505

2021.2022-1/2021.2022=2022-1/2021=2021.999505

 vì 2020.999505<2021.999505

=> 2020.2021-1/2020.2021 < 2021.2022-1/2021.2022